Summer days seem to be filled with millions of insects of all different varieties. They thrive in the warm temperatures that spring and summer bring. Then autumn comes and there numbers start to decline.
These insects are not simply dying off. They have developed many different strategies for staying alive during the cold winter months. Generally speaking, insects are not able to function when temperatures drop below 40 degrees Fahrenheit. You may notice that when temperatures start dipping into the lower 50’s or upper 40’s, your house begins to look a little more like the outdoors.
Ladybugs are the main thing people see coming inside when autumn comes around. Sometimes these little critters seem to be infesting houses by the thousands. I know they have become a sure sign that winter is not too far away.
Before humans built hibernation spots for ladybugs (ladybird beetles), they would overwinter in leaf litter, tree holes, and under rocks and logs. These are common hibernation spots for all adult insects. Some other insects that hibernate as adults are elm leaf beetles, cluster flies, boxelder bugs, honey bees, and Morning Cloak Butterflies. These insects commonly reduce their water content and build up a substance which acts as antifreeze called glycerol. This substance helps prevent them from freezing. Honey bees can actually raise the temperature in their hives by vibrating their wing muscles.
Other insects will migrate to warmer temperatures in the winter. A good example of these are Monarch Butterflies. These butterflies will actually fly to locations in the United States and Canada during the summer and return to Mexico and Southern California in the winter.
Some insects will lay eggs before winter which survive until the spring. Not as many insects use this method. Some that do are Corn Rootworms and Praying Mantids. Other insects will lay eggs that hatch before winter and the pupae or larvae will go into hibernation until the spring. Some moths employ this method.
Despite how it may look at this point, some insects actually remain active in the winter. These insects remain in their nymph stage during cold weather and live in water that does not freeze completely. They remain active, and grow through the winter, emerging as adults in the spring. Dragonflies and mayflies are good examples.
Next time you visit aVirginia State Parkduring the winter, remember that the insects are still all around you. Nature is truly breathtaking and demands admiration. This admiration may come to you a little easier while these insects are not flying around your face.